The purpose of this proposal is to foster the scientific development and clinical research skills of Dr. Erika Fernandez, so that she may become an independent clinical investigator, and to expand knowledge on the treatment of the hypotensive, ill newborn baby. Dr. Fernandez is an Assistant Professor at the University of New Mexico School of Medicine where she divides her time between research and clinical service in the newborn intensive care unit (NICU). Dr. Fernandez is currently working in an ideal setting in which to expand her investigations of relative adrenal insufficiency in the sick term and near-term newborn infant and the impact of hydrocortisone administration on cardiovascular function. Through collaboration with clinical mentor, Dr. Kristi Watterberg, and the expertise and support of the Neonatal Research Network (NRN), Dr. Fernandez will continue to build a foundation for the development of an independent academic career through didactic study of clinical research and experience in conducting this proposed study. A significant percentage of term, ventilated newborns may receive vasopressors for hypotension. In many of these infants, the etiology of their cardiovascular instability is unclear but the treatment is the same and includes varying prescriptions of fluid boluses and vasopressors. We have documented low cortisol values in a significant number of ill hypotensive newborns and plan to conduct a randomized multi-center placebo controlled trial of low-dose hydrocortisone to reduce exposure to vasopressors in these ventilated newborns. However, there is very little information concerning the current incidence and management of hypotension in this population. Therefore, we propose to collect these data as a necessary first step for the design of a large multi-center study of hydrocortisone. We hypothesize that a high proportion of ventilated term and near-term newborns admitted to the NICU at < 96 hours of age receive interventions aimed at alleviating cardiac dysfunction, particularly hypotension. We will define the incidence of hypotension for which therapy is administered and collect detailed information on interventions received for cardiovascular instability. Approximately 4,000 newborns will be enrolled from NRN Centers over one year, followed by analysis. The results of this study will lay the groundwork for further investigations of cardiovascular instability and relative adrenal insufficiency in this population which may impact clinical assessment, patient and outcomes. [unreadable] [unreadable] [unreadable]